README

   1 eccc_to_commons - Set of tools to replicate
   2                   Environment and Climate change Canada data on
   3                   Wikimedia Commons
   4
   5 This is a collection of scripts (mainly Bash and XSD/XSLT).
   6
   7 Most of them use standard Unix/GNU tools so it should work on any recent GNU
   8 distribution. In addition to coreutils, prerequisites are:
   9
  10 - Bash 4+
  11 - Curl
  12 - Xmlstarlet
  13
  14 This repository is sponsored by Environment and Climate change Canada and
  15 Wikimedia Canada.
  16
  17
  18 Provided scripts, ordered by chronological usage:
  19 dllist.sh                 outputs a curl configuration file listing all available
  20                           ECCC data
  21 eccc_fixer.sh             fix upstream data XML files
  22 eccc_fixer.xslt           fix upstream data XML file
  23 commons_rules.xsd         validate ECCC XML from a Wikimedian point of view
  24 eccc_to_commons.sh        transform ECCC XML files into JSON
  25 monthly_to_commons.xslt   transform ECCC monthly XML file into JSON
  26
  27
  28 Usage:
  29 The general idea of a large scale data import process is:
  30  1. Download a copy of all data required for the import
  31  2. Validate the cache
  32  3. Transform data into the target format
  33  4. Upload to the destination
  34
  35 These tools require some technical knowledge prior to using them so they aren't
  36 for general use. This is however a good starting point to discover how large
  37 imports are processed in community driven projects.
  38
  39
  40 In practice:
  41 Beside a reasonable amount of available disk space, you will have to create two
  42 distinct folders: the first will contain a copy of ECCC downloaded data while
  43 the second will contain the data to be uploaded to Wikimedia Commons.
  44 The following section will refer to them as ${ECCC_CACHE} and ${COMMONS_CACHE}.
  45 These environment variables must be set or replaced by valid paths when the
  46 commands are used.
  47
  48
  49 1.  Download a copy of all data required for the import
  50 1.1 Create a list of all ECCC provided files
  51 First, we generate a list of all the historical data provided by ECCC.
  52
  53  $ ./dllist.sh "${ECCC_CACHE}" > "downloads_all"
  54
  55 Expect quite long runtime. As of January 2020, it generates a list with almost
  56 650,000 download links.
  57
  58
  59 1.2 Filter unwanted files
  60 This long list may contain more files than you actually need, so you may want to
  61 reduce it so you don't have to download/store useless content.
  62 This step basically depends on your own needs, so not all cases will be covered
  63 here. downloads_all is a regular text file, so you can edit it with regular
  64 tools like sed, grep or your prefered interactive editor.
  65
  66 Here are a few examples to inspire you:
  67
  68 Keep only monthly data:
  69   $ cat downloads_all | grep -B1 -A1 --no-group-separator \
  70     -E '^output = ".*/monthly/[0-9]*.xml"$' > downloads_monthly
  71
  72 Remove all downloads before (restart interrupted download):
  73         $ sed -n '/https:\/\/climate.weather.gc.ca\/climate_data\/bulk_data_e.html?format=xml&timeframe=3&stationID=2606/,$p' \
  74           downloads_all > download_continue
  75
  76
  77 1.3 Download wanted files
  78 Give your own list of downloads to curl. You can add the parameters you need.
  79
  80   $ curl --fail-early --create-dirs -K download_all
  81
  82
  83 2 Fix the files
  84 Be aware the files you've downloaded is buggy. Yes, all of them, they're
  85 distributed as it by ECCC. But wait, there is a simple fix.
  86
  87 The clean way to perform the fix is to use the following script:
  88
  89   $ ./eccc_fixer.sh "${ECCC_CACHE}" "${ECCC_CACHE}-fixed"
  90
  91
  92 However, if you don't want to keep the original files, you can just do:
  93
  94   $ find "${ECCC_CACHE}" -type f -name '*.xml' -exec sed -i -e \
  95     's/xsd:schemaLocation/xsi:schemaLocation/;s/xmlns:xsd="http:\/\/www.w3.org\/TR\/xmlschema-1\/"/xmlns:xsi="http:\/\/www.w3.org\/2001\/XMLSchema-instance"/' {} +
  96
  97 From now on, the guide expects "${ECCC_CACHE}" to point the directory with fixed
  98 files only.
  99
 100
 101 3.  Validate the cache
 102 It's important you make the effort to validate the files before processing them.
 103 Every transformation makes assumptions on data structure/content that can only
 104 be asserted by using proper validation schemes. Bypassing this step may lead to
 105 not working transformations or invalid final data.
 106 This step is split in two: first we have to check the data is valid from an ECCC
 107 point of view and then we check it's valid through Wikimedian eyes.
 108
 109 3.1 Validate the data according to ECCC standards
 110 However, the XML schema distributed by ECCC is incorrect. It won't validate any XML
 111 coming from them. A fixed version can be found on Wikimedia Canada Git
 112 repositories.
 113
 114   $ git clone https://git.wikimedia.ca/eccc_schema.git
 115   $ find "${ECCC_CACHE}" -type f -name '*.xml' -exec xmlstarlet val -b \
 116     -s eccc_schema/bulkschema.xsd {} \;
 117
 118 The second command will list all incorrect files. If output is empty, you can
 119 continue.
 120
 121
 122 3.2 Validate the data according to Wikimedia standards
 123
 124   $ find "${ECCC_CACHE}" -type f -name '*.xml' -exec xmlstarlet val -b \
 125     -s commons_rules.xsd {} \;
 126
 127 Same as previously, the output should be empty. Otherwise, you must resolve
 128 every single problem before continuing.
 129
 130
 131 4. Transform data into target format
 132 Here we are, here is the fun part: let's create weather data in Wikimedia
 133 Commons format.
 134
 135   $ ./eccc_to_commons "${ECCC_CACHE}" "${COMMONS_CACHE}" 2>log
 136
 137 It will replicate the future Commons content paths inside nested directories.
 138 So, for example future
 139 https://commons.wikimedia.org/wiki/Data:weather.gc.ca/Monthly/4271.tab resource
 140 will be created in ${COMMONS_CACHE}/weather.gc.ca/Monthly/4271.tab.
 141 A sum up log file is created for further reference on what has been done during
 142 conversion.
 143
 144
 145 5. Upload to destination
 146 Not done yet.